Exploring the Humane and Canine Microbiome

Dr. Robynne Chutkan, one of the leading gastroenterologists in the country, is the author of a new book, The Microbiome Solution, in which she takes us on an exploration of our guts’ ecosystems. Her rousing endorsement of “living dirty” includes the benefits of living with dogs. Bark’s editor speaks with her about just how helpful dogs are to our health, inside and out.

Is it true that there are similarities between our microbiome and those of our dogs, and that dog-owning families have more diverse microbial colonies than dogless households?

Although we share many of the same microbes, dogs in general have a more diverse microbiome than we do. Not surprisingly, some of their additional species are soil microbes (rolling in the dirt from time to time may be a habit worth copying!). Close contact with our dogs is hard to avoid, and that’s a good thing, because they end up passing on some of their unique microbes to their owners, giving dog-owning households a microbial boost.

Dog owners who have children share more mouth bacteria with their dogs than they do with their children. Is this a good thing?

The microbiome in children under the age of three is still developing and as a result, is very different from that of an adult, although there are still lots of shared species with household members (and pets), given the proclivity children have for [putting] everything in their mouths. So, most adults (not just dog owners) have a very different microbiome from their young children. As children get older, their microbiome starts to more closely resemble that of the other household members—not just parents, but pets, too. The vast majority of microbes our canines pass on to us are helpful or benign, not harmful, so keep those doggie kisses going.

So bacteria aren’t species-specific? Is that why, as you note, owning a dog is a highly effective way to replenish and revive bacteria that are basically under attack by modern-day living?

Some bacteria are species-specific, but many are shared by both humans and dogs. Most dogs are much more in touch with the natural world than their owners are, and that’s exactly where lots of the health-promoting microbes come from: soil; unfiltered, unchlorinated water; and, of course, the poo of other animals that our dogs are constantly checking out. Dogs tend to go easy on the hand sanitizer and antibiotics and eat a less processed diet (all habits worth emulating), so they haven’t super-sanitized away as many of their microbes as we have. Some of these canine microbes can be passed on to us, helping to replenish our lackluster microbiome.

The high-fat, low-fiber food we eat, attracts a different range of microbial types; do you know if that is the same for dogs?

I’m not aware of any specific studies looking at variations in canine diets and the effects on their microbiome, but certainly, dogs who eat more processed grains and other foods not natural to their diet tend to have more health problems, and the same is true for humans.

You mention that it’s okay to be a little dirty and sweaty. Why do you think Americans are so obsessed with being hyper-clean?

In the pre-antibiotic era, epidemics of the plague, cholera and other highly infectious diseases wiped out vast numbers of people. The advent of penicillin in the 1930s is still one of the most important contributions to modern medicine, and antibiotics have saved countless lives. But now the pendulum has swung the other way; we’re currently in an era of overdiagnosis and over-treatment, and we’re seeing the emergence of new “modern plagues,” not from infection, but from not enough microbes.

However, the public still sees antibiotics as the life-saving miracle workers they were in the first part of the last century, not as the overprescribed menace they’re becoming. Plus, 80 percent of all antibiotics sold in the U.S. are used in the livestock industry, mostly to fatten animals for slaughter. Clearly, that’s not a lifesaving endeavor.

I think the pharmaceutical and personal-product companies also have a lot to do with it. They’re responsible for many of the public-health campaigns that incorrectly equate cleanliness with health, and of course, they make billions of dollars selling hand sanitizer and other anti-bacterial products.

It’s not just okay to be a little sweaty and dirty, it’s great for your microbiome and your overall health. We need exposure to dirt and germs (bacteria, fungi, protozoa and so forth) to train our immune systems to recognize friend from foe. Not enough exposure to germs, especially when we’re young, leads to a confused immune system that tends to overreact. The result is allergies and autoimmune diseases.

In defense of less bathing and shampooing: your body is really good at concocting the exact formula needed to keep your skin and hair moisturized and healthy. But what do we do? We scrub away our natural oils with harmful antibacterial products and then try to revive our skin and hair with store-bought products full of chemicals. Live dirty for a healthier— and better looking—you!

Many studies have shown the benefits to children of having a dog, including a decrease in eczema and asthma. Why else would you recommend that a family get a dog?

Having a dog is great for reducing stress and anxiety and lowering blood pressure. And we already know they improve the microbiome of the entire household.

What’s your personal dog “biome”?

My mother’s bridge partner, Eva, worked for the Swedish embassy, and when she moved back to Sweden, she left her beloved German Shepherd, Trygg, with us. He’d been used to spending all his time with Eva, and became immediately attached to my mom. We had to be super vigilant in the bathroom because he loved to drink from toilets (all kinds of rewilding going on!).

Hugo, our German Shorthaired Pointer puppy, came into our lives about six months ago. Getting a dog forced me to slow down my too-busy lifestyle and spend more time sitting on my front steps, stroking Hugo and literally smelling the roses. He’s super active, so my husband and I take turns running with him in the mornings and evenings.

We live near Rock Creek Park in Washington, DC, so, thanks to Hugo, there’s a whole lot of dirt and sweat happening on a daily basis. Our daughter Sydney loves him so much that we really can’t imagine life without him.

Hugo slobbers over everyone he comes into contact with, and since I frequently have meetings with the Gutbliss team at our house, he’s become our CRO—Chief Rewilding Officer!